Grid trading bot: it only works inside the box

Grid trading, in this design, places buy orders below the current price and sell orders above it, at steps you choose, and only between a floor and a ceiling you also choose. Each round trip that completes inside the box collects the step, minus fees. The round trip is not a wage. It is a small spread you hoped would repeat.

Inventory is the quiet position

When price falls through several rungs, the buys fill and the sells stay up where price no longer is. You are then holding more of the coin than the picture of a tidy ladder suggested. That inventory is a directional position. Calling the grid market-neutral does not make the coin stop moving. The design refuses that label.

The mirror case is a rise that fills the sells and leaves you holding quote currency, watching the coin leave the top of the box. You did not 'miss' in the sense of a bug. The rule sold because that is what a grid does at the upper rungs. If you needed the coin to remain, a grid was the wrong rule.

Fees can eat the step

A narrow step on a market with a wide fee is a machine that trades in order to pay the venue. The arithmetic is unromantic: if the fee on the round trip is larger than the distance between rungs, the completed cycle is a loss even when both orders fill at the prices you asked. Captay will not search for a step that survives the fee. You would have to measure it, later, in paper mode. You cannot measure it here.

Outside the box, the grid stops

The intended behavior when price leaves the range is to stop, not to chase. Chasing means dragging the box along a trend and discovering that you have built a larger position with a new name. A maximum inventory sits beside the price box so that even fills inside the range cannot quietly become the whole account. Daily loss and drawdown still wrap the strategy. A grid that is allowed to ignore them is not a Captay grid.

None of this is market making for a rebate, and it is not an arbitrage against another venue. There is one exchange in the picture, the one where your coins already sit, and there is no rebate contract described on this site because none exists.